Protection of combination locks against entry by radiography



May 31, 1960 E. L. CRISCUOLO ETA 2,938,374

. PROTECTION OF COMBINATION LOCKS AINST ENTRY BY RA GRAPHY Filed June1957 FIGJ. FIG.4.

GO D-O OCXYYXXX] INVE ORS.

I 31 EDWA L. c CUOLO DAN POLANSKY DONA D P. CASE BY jl/flb;

ATTYS.

United States Patent PROTECTION OF COMBINATION LOCKS AGAINST ENTRY BYRADIOGRAPHY Edward L. Criscuolo, 10803 Keller St., Silver Spring, Md.;Daniel Polansky, 11123 Dewey Road, Kensington, Md.; and Donald P. Case,702 Brantford Ave., Silver Spring,

Filed June 24, 1957, Ser. No. 667,725

8 Claims. (Cl. 70333) (Granted under Title 35, US. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

The present invention relates to a protected combination lock, and moreparticularly to the protection of a combination lock against entrythereof by radiography, and a method and means for affording saidprotection.

Present day combination locks employ tumblers and arrange them in amanner that the lock is fairly well protected against mechanicalmanipulation thereof. However, X-rays or other penetrating radiation maybe used to locate the positions of the openings or gates in the tumblersand thereby determine the combination of the lock. Moreover, with thedevelopment made in portable penetrating radiation sources in recentyears, a safe or tered on the premises by a radiographic method and thecombination setting of the lock can be obtained within a relativelyshort period of time without leaving any visible evidence of suchcompromise, This possibility has been recognized by those working in thelock art and it has been proposed to modify the construction of thetumblers to the end that the tumbler openings cannot be rendered visiblefrom the exterior of the lock casing by the use of X-ray or the rays ofradioactive isotopes, see US. Patents 1,847,071, 1,925,980 and 1,928,-853 to William F. Doenges. However, such measures were not completelysuccessful for the reason that the X-ray absorption characteristics ofthe materials employed were such that a sufficient definition of thetumblers could be obtained under appropriate conditions with the resultthat the combination could be determined for unlocking the lock.

In accordance with the present invention, the tumblers of the lock areformed of material having low X-ray absorption characteristics, a shieldof material having high X-ray absorption characteristics is providedaround the lock, and finally the shielded lock is located betweenmembers of material having X-ray scattering characteristics.

It is therefore an object of the present invention to provide a lockprotected against entry by radiography.-

Another object'is the provision of a lock having tumblers therein of asuitable plastic material, such, for example, as Tefion or nylon.

A further object is to provide a lock having tumblers of a materialhaving low X-ray absorption characteristics, such as nylon and a shieldthereabout of material having high X-ray absorption characteristics,such as lead.

A final object of the present invention is the provision of a lockhaving plastic tumblers and lead shielding, and disposed between membersof X-ray scattering material, for the purpose of preventing sufficientdefinition of the tumblers and thereby preventing compromise thereof byradiography.

container protected by a combination lock may be en- With these andother objects in view, as will hereinafter more fully appear, and whichwill be more particularly pointed out in the appended claims, referenceis now made .to the following description taken in connection with theaccompanying drawing in which:

Fig. 1 illustrates schematically the arrangement of the critical partsof a lock protected in accordance with the present invention, and therelation thereof with respect to an X-ray source and an X-ray film;

Fig. 2 is a side elevation, in section, of a conventional combination orpermutation lock protected in accordance with the invention;

Fig. 3 is a sectional view taken on line 3-3 of Fig. 2, looking in thedirection of the arrows; I

Fig. 4 is a fragmentary view of one form of X-ray scattering material;and

Fig. 5 is a fragmentary view of another form of X-ra scatteringmaterial.

Referring now to the drawings, wherein like reference charactersdesignate like or corresponding parts throughout the several views,therein is shown in Fig. l a schematic arrangement serving to illustratethe principle of operation of the present invention, the referencecharacter 11 designating lock tumbler material having low X-rayabsorption characteristics, which in turn is flanked on all sides by'shield material having high X-ray ab.- sorption characteristics anddesignated by reference character 12 The tumbler material is alsoflanked on all sides by material 13 which has the properties ofscattering X-rays, the shield material 12 being disposed between thescattering material 13 and the tumbler material 11. A suitable source ofX-rays, or radiation from a radioactive isotope, is designated byreference character 14, while reference character 15 designates suitablefilm for exposure to the radiation which passes through the lock andassociated parts to form a radiograph thereof.

Turning now to Fig. 2, which shows the invention applied to aconventional combination or permutation lock, with parts in section fora better understanding of the relationship therebetween, referencecharacter 16 designates a portion or panel of the safe or container uponwhich the lock is mounted, the lock, except for the tumblers thereof,being of conventional character and having the usual operating shaft 17,one end thereof being disposed within the safe or container, the otherend disposed exteriorly thereof. The exterior end of the operating shaft17 carries a conventional numbered dial 18 and an operating knob 19, thesafe or container panel 16 having thereon a suitable index mark [notshown] at the periphery of the dial.

The inner end of the operating shaft 17 extends into a box or casing 21and is secured to a primary driving wheel 22 disposed in the box, theWheel being rotatable through the medium of the operating knob andshaft. Box 21 has a back plate 23 and fixed thereto is a hollow post 24into which the inner end of the shaft 17 telescopes, the post beingadapted to support a plurality of rotatable members 25 which areretained thereon by means of a resilient snap ring or retainer 26adapted to seat 'within a groove formed in the post adjacent the freeend thereof. The rotatable members 25 are maintained in spaced relationon the post by using washers which are connected to remain fixed to thepost and serve to prevent the transmission of rotation of one of therotatable members to the adjacent rotatable member except through thepin and fly" connection between the rotatable members, neither thewashers nor the pin and fly connections being shown, but readilyunderstood by those skilled'in the art.

A pin and fly connection also exists between the primary drive wheel 22and the rotatable member 25 nearest thereto, whereby said rotatable.member may be rotated by turning the operating knob 19. Because of thepin and fly connections between the rotatable members 25, the rotationof the first such members is transmitted to the neat member and so onthrough the several members arranged on the post. Thus, by propermanipulation or turning of the operating knob, according to thecombinatiori or setting of the rotatable members 25, these members arebrought into a predetermined relationship which permits releasing of thelock mechanism and the nnlo cking of the safe or container.

' Ordinarily, each of the rotatable members 25 is made in two parts, aninner part 28 rotatably mounted on the Pa t aflslansi er p 29 ri by s in rat the outer periphery of the inner part and the inner periphery ofthe orrter part being suitably serrated for intermeshing connection toeach othen thereby providing for the outer part to he slipped off andset with respect to the inner part, suitable indic'ia being providedwhereby any desired set: .ti ng may be made. The outer part29'constit'utes a tumbier or tumbler Wheel and has formed in the outerperiphery thereof a notched opening or gate 3 l, the setting orcombination .of the openings or gates being determined In the eventfuture technological developments make it po'ssible to detect thetumbler openings, "each tumbler could also be provided with severaldummy gates which would have therein a thin web of material to preventthe by setting eachouter part 29 with respect to its inner part 28, as.hereinbefore described. When the tumbler openings or gates have beenrotated into alignment by proper manipulation of the operating knobaccording to the cornhination or setting of the terminal, the fence endof the lock bolt (not shown) can move into the aligned openjhgsto permitreleasing of the lock mechanism by turning ,of theo'perating lrnob 19.The hereinbefore described parts ,of'the lock, and the operation.thereof, should be readily understoodby those skilled in the art andfurther description thereof appears unnecessary. i

' In the application'of this invention to theconventional lock,hereinbefore described, firstly, the outer part 29, in whichjs formedthe tumbler opening or gate,'is madeof a material having low X-rayabsorption characteristics; that is, a low density material such asnylon, Teflon, Bakelite, etc. Secondly, the box 21 is contained in ahousing 32 made of material having high X-ray absorptioncharacteristics; that is, a high density shield material, such .as leador the .likeQa suitable bo're or opening 33 being provided therein forpassage of the operating shaft 17 therethrough. Thirdly, the box isflanked ,onall six sides by layers of material 34 havinghighX-rayscattering characteristics and disposed exteriorly ofthe shield .aa srialt flEheXray scatter material may take several forms, such sfiS, aplain' .steel iplate, aplate with drilled holes, or a layerp'f steelballs. Fig. 4 shows a steel plate 35 drilled with holes 36, the holesbeing inch in diameter and spaced /2 inch on centers with the maximumnumber of holes possible being drilled in the plate, .the thicknessthereof being 3/ inch. Fig. 5 illustrates Xsray scattermaterial-intheformo'f a layer of steel balls 37, preferably FA chdiametenlsuc h layer of balls being adapted to h spata iwdii h s i livus ns a -Part bf which suitably hollowed out to'receive the .b'alls,the balls being held ,in 1 place ;by means .of. plates secured ,to thehousing,

. orby being moldedin amatrix of plastic 38, as illustrated In n ofthete t 0 th inten n m iasfien-ls wasfitted with three Mi inch nylohturnbers, with the vappropriate notched openings or gates therein.Placed on I allsigr sides of vthelock was /2 inch leadshield materialand inch diameter steel balls. Thus, the radiation p t ex sndq 1th v tht 1%? n yl mmb st -the total of l inch of lead and two layers of inchdiameter steel balls. .placedon a file drawer anda radiograph-was tak e-em- 'ploying-a radioaetive source. :Inthe ;r adiograph,;althonghvarious parts of the lock were visible, the notched .op en- '=ingston-gates in .the tumblers were undefinedand lOSt. fSUCh lOCkS areconsidered :fully protected against entryby -radiographic methodss-ormeans: v

he la k as rat s? wa materi fence of the lock from entering therein.Extreme dithculty will therefore be encountered in determining the truetumbler gates or openings, thereby concealing the proper settingsthereof for protection of the lock against adve csd ra i sranhi me h dan means- -.Con,siderati on of all the factors effecting the protectionof combination locks from radiographic comprise has lead to theselection of low density tumbler material because of thediflicultdetection problem presented thereby, the use of lead shieldingfor limiting the selection of radition sources to those with highenergy, and the employment of efficient scattering material forscattering the radiation rays; Presently, the optimum protective systemis considered to consist of nylon tumblers, a /2 inch of lead on eachside, and a layer of /4 inch diameter steel balls outside the lead. Withthis system, as much as 0.7 inch of nylon can be utilized in the lockwithout being detected radiographically.

' From the foregoing, it should be apparent that'there has beenprovideda combination lock which is fully proaga'inst compromise by radiographicmeans or methods and that such protected lock represents an embodimentof the present invention.

Obviouslym'any modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than 'as specifically described. I What isclaimed as new and desired to be secured'by Letters Patent of the UnitedStates is:

'1. A loch protected agains radiographic compromise, comprising a lockincluding tumblers made of a low density material, a casing for saidtumblers, a housing contacting said casing for shielding said tumblers,said housing being of a high-density, X-ray absorbing material, andlayers of material contacting said housing and having the capability ofscattering penetrating X-ray radiation impinging thereon.

A lock protected against radiographic compomise, comprising a lockincluding tumblers made of a low density material, a housing surroundingsaid tumblers for shielding the same, said housing being of a highdensity material, and layers of material flanking said tumblers andhaving the capability of scattering penetrating radiasign impingingthereon, said layers of material being metal l st sihi' ii hl reas f m dt e 3. A look protected against radiographic compromise,

. A look protected against radiographic compromise,

said lockcomprising a housing made of material having high X-raypenetrating radiation absorption characteristics and formed with aninternal chamber, said housing having exterior'portions thereof flankingsaid chamber and holdowedout for providing shallow cavities therein,X-ray penerating radiation scattering material disposed in each oi saidcavities, lock tumbler and casing means contained incsaid chamber, saidcasing means being in contact with said housing, and said tumbler meansbeing made oi a hat iri ,l .X-re Pe -F ing r io a 5. A lock as definedin claim 4 the materiallof Bassist betas has}. sad th states hesbstwssas 5 chamber and said scattering material being at least onehalfinch.

6. A lock protected against radiographic compromise, said lockcomprising a housing made of material having high penetrating radiationabsorption characteristics and formed with an internal chamber, saidhousing having exterior portions thereof flanking said chamber andhollowed out for providing shallow cavities therein, penetratingradiation scattering material disposed in each of said cavities, andlock tumbler means contained in said chamber, said tumbler means beingmade of a material having low penetrating radiationabsorptioncharacteristics, said scattering material including a layer ofonequarter inch steel balls.

7. A lock as defined in claim 4, said last-named material being nylon.

8. A lock protected against radiographic compromise and comprisingtumbler means made or" nylon, a casing for said tumbler means, a housingmade of lead contacting said casing, and layers of X-ray scatteringmaterial flanking said tumbler means and secured to said housing.

References Cited in the file of this patent UNITED STATES PATENTS OTHERREFERENCES General Electric Review of March 1939. Pages 109 to 1 13.

